More Men Defer Treatment for Low-Risk Prostate Cancer

Dramatic rise in Swedish study but uptake lags in U.S.

Action Points

Active surveillance has become the dominant management strategy for low-risk prostate cancer in Sweden, with the highest rates yet reported and almost complete uptake for very-low-risk cancer, according to a database study.

Note that the researchers aimed only to study initial treatment selection by contemporary cases, and the study did not include follow-up data on active surveillance outcomes.

Three-fourths of men with low-risk prostate cancer opted for active surveillance as their initial strategy for clinical management, according to a study of Swedish men from 2009 through 2014.

More than 90% of men with the lowest-risk forms of prostate cancer chose active surveillance. Use of active surveillance increased by 60% to 85% over the study period among men with very-low and low-risk prostate cancer. The biggest increase occurred during the last 3 years, reported Stacy Loeb, MD, of NYU Langone Medical Center in New York City, and colleagues.

However, men with intermediate-risk prostate cancer, and their physicians, remained reluctant to use active surveillance, they stated in JAMA Oncology.

"Active surveillance has become the dominant management for low-risk prostate cancer among men in Sweden, with the highest rates yet reported and almost complete uptake for very-low-risk cancer," the authors concluded. "These data should serve as a benchmark to compare the use of active surveillance for favorable-risk disease around the world."

Active surveillance has begun to evolve into an international standard of care for men with low-risk prostate cancer, said Matthew Cooperberg, MD, MPH, of the University of California San Francisco, in an invited commentary. However, uptake of active surveillance in the U.S. continues to lag behind rates seen in other developed nations.

"A growing body of evidence indicates that active surveillance can preserve quality of life without posing substantial short- to intermediate-term oncologic risk," said Cooperberg. "Based on this evidence, a recent guideline endorsed by the American Society of Clinical Oncology [ASCO] now clearly states that surveillance is not merely an option for men with low-risk disease but rather is the preferred alternative for any clinically localized, Gleason 3 + 3 cancer.

"From this perspective, given that most men with low-risk tumors who undergo any therapeutic intervention face substantial likelihoods of overtreatment, active surveillance rates for low-risk disease are still too low in the United States."

With recent changes in pathology grading practices, the reach of active surveillance could extend safely to carefully selected men with Gleason 3 + 4 tumors and remain consistent with the ASCO guideline, he added.

Loeb and colleagues previously examined uptake of active surveillance and watchful waiting among Swedish men with newly diagnosed prostate cancer through 2011, using the country's National Prostate Cancer Register. They performed an updated analysis, examining uptake of active surveillance and watchful waiting from 2009 through 2014.

The new analysis comprised 32,518 men who had a median age of 67. All had newly diagnosed favorable-risk prostate cancer, further categorized as:

The total study population comprised 4,693 men with very-low-risk disease, 15,403 with low-risk disease, and 17,115 with intermediate-risk prostate cancer. Across all risk groups, 35% used active surveillance, 8% used watchful waiting, and 5% chose androgen deprivation therapy.

Analysis by risk group showed that use of active surveillance and watchful waiting increased from 64% to 93% in patients with very-low-risk prostate cancer and from 50% to 79% in patients with low-risk disease, but decreased from 26% to 25% for patients with intermediate-risk disease.

The analysis of active surveillance alone showed the uptake increased from 57% to 91% among patients with very-low-risk disease and from 40% to 74% for patients with low-risk disease (P<0.001 for both comparisons). Use of watchful waiting decreased during the study period.

Use of active surveillance increased in all age groups (<60, 60 to 69, and ≥70). For men with very-low-risk disease, the rate increased from 44% to 88% in men 50 to 59, 64% to 95% in those 60 to 69, and 53% to 84% in those 70 or older. In the low-risk group, uptake of active surveillance increased from 30% to 68% in men 50 to 59, 43% to 79% in those 60 to 69, and 44% to 67% in men 70 or older.

"Even among men younger than 50 years, active surveillance increased, to 89% and 43%, among men with very-low-risk and low-risk disease by 2014," the authors noted.

Overall, use of active surveillance in men with intermediate-risk disease remained low throughout the study period. However, the rate increased from 31% to 53% in the subgroup of men with Gleason score 6 and PSA 10 to 20 ng/mL.

The study had some limitations, such as the fact that the definition of active surveillance among some clinicians became less stringent for men ages 70 and up. The authors explained that more than twice as many men younger than age 70 on active surveillance had a repeat biopsy versus men ages 70-plus.

Also, the study did not include follow-up data on active surveillance outcomes, but the authors pointed out that their aim was to study initial treatment selection by contemporary cases.

The study was supported by the Swedish Research Council,the Swedish Cancer Society, the Västerbotten County Council, the Louis Feil Charitable Lead Trust, the Laura and Isaac Perlmutter Cancer Center at New York University Langone Medical Center, and the NIH.

Loeb and co-authors disclosed no relevant relationships with industry.

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